//*****************************************************************************
// Copyright 2017-2020 Intel Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//*****************************************************************************

#pragma once

#include "ngraph/node.hpp"
#include "ngraph/pattern/op/pattern.hpp"

namespace ngraph
{
    namespace pattern
    {
        namespace op
        {
            class Branch;
        }
    }
}

/// A branch adds a loop to the pattern. The branch match is successful if the
/// destination node pattern matches the graph value. The destination node is a node in
/// the pattern graph that will not have been created some time after the Branch node is
/// created; use set_destination to add it.
///
/// The branch destination is not stored as a shared pointer to prevent reference
/// cycles. Thus the destination node must be referenced in some other way to prevent it
/// from being deleted.
class NGRAPH_API ngraph::pattern::op::Branch : public Pattern
{
public:
    static constexpr NodeTypeInfo type_info{"patternBranch", 0};
    const NodeTypeInfo& get_type_info() const override;
    /// \brief Creates a Branch pattern
    /// \param pattern the destinationing pattern
    /// \param labels Labels where the destination may occur
    Branch()
        : Pattern(OutputVector{})
    {
        set_output_type(0, element::f32, Shape{});
    }

    void set_destination(const Output<Node>& destination)
    {
        m_destination_node = destination.get_node();
        m_destination_index = destination.get_index();
    }

    Output<Node> get_destination() const
    {
        return m_destination_node == nullptr
                   ? Output<Node>()
                   : Output<Node>{m_destination_node->shared_from_this(), m_destination_index};
    }

    bool match_value(pattern::Matcher* matcher,
                     const Output<Node>& pattern_value,
                     const Output<Node>& graph_value) override;

protected:
    Node* m_destination_node{nullptr};
    size_t m_destination_index{0};
};
